a woman divorced or otherwise separated from her husband
a woman whose husband is often away for short periods of time
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word origin of 'grass widow'Early ModE, discarded mistress (similar to Du grasweduwe, Ger strohwittwe): prob. allusion is to bed of grass or straw as opposed to the conjugal bed